RELATIONS OF CORXEAL CORPUSCLES TO MATRIX. 405 



The brown tint immediately disappears when the specimens 

 are dipped into the latter solution. If, after they have 

 macerated in it as long as when prepared by this means alone, 

 and are then exposed in very diluted acetic acid to the direct 

 action of light, they rapidly acquire a blue colour. This re- 

 duction, as may easily be seen under the microscope, is effected 

 by the matrix. And now the same stars and anastomosing 

 processes are seen in the blue matrix as in the silvered speci- 

 mens, which is essentially due to the fact that the cell sub- 

 stance and nuclei, where these are still preserved, become, by 

 impregnation with the chloride of gold, prominently visible, 

 owing to their distinctly granular aspect and light yellow 

 colour. This may be satisfactorily demonstrated in cases 

 where the nitrate of silver has only acted for a short time, 

 filling these cavities and their processes ; for the corneal cor- 

 puscles are then distinctly visible in a somewhat swollen 

 condition. If the action of the nitrate of silver has lasted 

 for a longer time, or if the cornea has been too much wasted, 

 which however is to be avoided, the cells and their pro- 

 cesses appear still more swollen, and the cavities in the 

 matrix are correspondingly altered. If the silver salt have 

 acted for a still longer period, the cavities in the matrix appear, 

 in the specimens subsequently submitted to the action of gold, 

 empty, and the cells destroyed. We shall hereafter again 

 refer to these preparations. The staining of silvered cornese by 

 means of logwood is also to be recommended for this purpose, 

 but the results do not surpass those obtained by the combined 

 silver and gold method. 



I have already (p. 387) stated that the most remarkable 

 phenomenon accompanying the electrical excitation of the 

 cornea is the apparition of the contour lines of the cavities of the 

 matrix.* The distinctness with which I see this phenomenon, 

 and the unfailing certainty with which I can demonstrate it, 

 render it difficult for me to understand how it has escaped 

 observation. 



* A. Rollett, Ueber die Contractilitat der Hornhautkorperchen und die 

 Hornhaut-hohlen, (On the contractility of the corpuscles and cavities of 

 the cornea,) Centralblatt fur die medicin. Wissenschaften, 1871, No. 13. 



